The specific aim of this research is to study in detail the organization of the retinotopic and tonotopic projections from the visual and auditory cortical regions within the striatum. These findings will be compared with that of somatotopic projections from the motor and sensorimotor cortex to the straitum in cats. The neurons that project to the straitum from architectonically different regions of the visual and auditory cortex will be identified and compared with the available information relating to the cells of origin of other corticofugal projections. The corticostriate projections will be studied by injecting minute quantity of 3H proline in motor, sensorimotor, auditory and visual cortical regions in adult cats. The identification and the study of the different morphological properties of the corticostriate neurons will be done with the recent modifications of the horseradish peroxidase techniques using benzidine dihydrochloride and tetramethyl benzidine. The sections of the brains will be studied under brightfield and dardfield microscopy, photographed and projection drawings will be made with the aid of camera lucida apparatus. Histograms will be made when indicated. The results obtained from these experiments will fill the gap in our knowledge of the intrinsic organization of the corticostriate projections, with particular reference to the sensory cortical areas. These results will provide basis for future research to understand the role played by the sensory cortical regions in normal and abnormal involuntary movements, about which we know very little now.